To get a "true" 1/4 inch seam, you raise your neede to it's highest point. Slip your smallest quilting ruler under your needle (I use my 1x12) and slowly...by hand...lower your needle so it just touches the 1/4" line on your ruler. Mark your sewing machine with a post it note right up against the edge of your ruler. Raise the needle and remove the ruler. You can now tape down the post-it.